Счёт на оплату (PDF с QR-кодом)

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false, openWorldHint=false, idempotentHint=false, destructiveHint=false, but the description goes further and adds genuinely useful behavior: it validates INN/KPP/BIK and BIK consistency and refuses to write the file on error, it writes the PDF to disk (side effect location), it needs no network, and it returns the path plus computed totals and the PDF itself.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then validation behavior, then sibling routing, then side effects — a sensible order with no filler sentences. It is dense, but every clause carries information; only the fine-grained enumeration of document parts is slightly over-detailed.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 12-parameter, nested-object tool with no output schema, the description covers the missing pieces: what the return contains (path, sum/vat_amount/total/total_words, the PDF), the validation-and-abort behavior, and the on-disk side effect. An agent has everything needed to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all 12 parameters, including the VAT enum values and the note that QR requires seller bank details. The description's mentions of НДС/«Без НДС» and сумма прописью largely restate what the schema and the returned-totals list already convey, so it adds little beyond the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and artifact (создаёт счёт на оплату в PDF по типовой форме) and enumerates the exact document contents: bank block, parties, line items, totals, VAT, amount in words, signatures, QR per ГОСТ Р 56042. It also explicitly separates itself from the closing document (act_create) and the standalone QR tool (payment_qr), so an agent can route without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Names both alternatives and the condition that selects each: act_create for a closing document, payment_qr when only the QR is needed, invoice_create for the invoice itself. It also states the precondition (INN/KPP/BIK validation must pass, otherwise no file is produced).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.